Businesses relying on MailChimp to deliver their marketing and sales emails are caught up in a battle between online service providers that could mean their emails are only reaching a fraction of their intended audience.

In an email to StartupSmart’s publisher Private Media, MailChimp confirmed it had been experiencing domain name server issues with .au based domains.

“After investigation, we are aware that TTP Wholesale, one of Australia's service providers, does have some sort of block in place against our DNS servers,” the email says.

“Since this block was discovered, we have been proactively working with this provider specifically to get our DNS IPs unblocked, and trying to provide as much assistance to them to demonstrate how these blocks are in turn affecting their customers.”

MailChimp says they are already working with the company involved, adding the best thing Australian users can do is reach out to their hosting company to explain how the blocks are affecting their businesses.

MailChimp has proven very popular in the SME space as a result of its free pricing plan for small mailing lists (MailChimp delivers your messages for free so long as you include an advertisement for MailChimp in your email), so a blacklisting of this scale is a very big deal.

If you have been affected by this block, please don't hesitate to contact us for advice - we've moved a number of clients off MailChimp to alternative providers.